Q&A: A Forum for Green Building Experts and Beginners

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Hello. I was reading the article by Martin Holladay entitled "Solar Thermal is Really, Really Dead" and enjoyed the discussions going back and forth on the topic of solar water heating methods. I am planning on building a small 600sq' SIP cabin in the area of Nelson BC (climate zone 6) next year and I found this product listed as being one of the most efficient for heating domestic hot water on the Canada Energy Guide site. It says it can also be used for space heating via a radiant floor system or perhaps radiators.

I'm renovating a small outbuilding on a farm (15' x 15'), which has slab on grade foundation. The slab is sitting on crushed stone but has no vapor barrier underneath. I have put a 10 mil poly sheet on top of the slab, and 2x4 joists (sleepers) on top of the poly sheet. My plan was to now spray foam insulate (about 2" - 3") on top of the poly sheet, then install subfloor and then hardwood. However, before spray foaming, I can see significant water pooling under the poly sheet. Probably to be expected, but somewhat surprised at how visible.

Working on plans for my next home. After lots of research on here and others I am considering the following wall assembly. From the exterior... wood siding, tar paper, 1/2" plywood with taped joints, 2x4 ,16 on center wall stud with roxul, uniterupted layer of 1 1/2" comfort board, layer of a variable perm vapor barrier (taped seams and such), then a layer of 2x3 installed 2 ft. on center as battens for electrical with shallow boxes , second layer of comfort board fit between the battens, drywall finish. I am in zone 5 in northern ct.

Zone 5 - helping with a wall design. They are using 2x8s for studs to fit in R-30 mineral wool. I am suggesting rigid foam, EPS or XPS, but I have only read that 2x6 wall needs R-7.5 But, this is a 2x8 wall, and I don't think R30 is traditional. So Will 2" of XPS or EPS be sufficient? Don't really want to have to go with two sheets and achieve 2.5" of rigid foam if 2" is sufficient with R30 mineral wool on the interior.

Is there any way to make 2" work? Such as a smart membrane installed before drywall?

I am in the process of renovating a 1-level 470 sq ft basement walkout condo in Kittery, ME. It has two floors above it. I've consulted a contractor, and don't agree with their suggestion for a mini split. So, I've started doing research!

I was excited about using the Sanden CO2 HPWH, but communication with the company was very hit or miss. The local installer they referred me to was very responsive and helpful with technical information. He gave me a quote for $5,900 installed. This was for a 43 gallon tank (the 83 gallon tank, oddly enough, would've been $6,100 installed). Because of the poor communication, and the cost, we had to move on.

The easily obtainable heating capacity information for ductless heat pumps are generally listed as Btu/h at 47 degrees and Btu/h at 17 degrees. These don't appear to line up with the expanded capacity charts which can (sometimes) be found with some digging on manufacturers websites. Let's look at the Fujitsue ASU9RLS3:

I have to replace my 28 year old ventilating heat pump water heater (leak in tank) and can't find anything to fit the bill. My unit doubles as an air to air heat exchanger. When the water heater cycles on, air is ducted from the bathroom & kitchen, across the coil in the heat pump, and outside. Fresh, replacement air is allowed into the house through small openings in outside walls in bedroom closets. None of the heat pump water heaters I've found allow for ducting in although some can be adapted for ducting outside.

Hi All! Does anyone have specific experience using India Ink on hardwood floors?

I am in need of specific information on how to seal the floors once they are stained. I've asked around a few woodworking/DIY sites and while people offer idea's, it doesn't seem like anyone can give me an answer on a tried and true product and means of application. What product and what means of application can be used to seal India ink on hardwood floors? All suggestions, completed project examples and even failed attempts helpful!

I am building a net zero house, 2000 SF, 2 stories. Can you tell me the pros and cons of the Lunos e2 ductless HRV system vs. a ducted system? The rep told me that 3 pairs of the Lunos e2 would be about right.